It's hard to think of a time when Little Mix and One Direction weren't part of the pop scene.
But yes, it is true, and it just so happens that both groups - who became famous on The X Factor - are celebrating some big anniversaries at the same time.
First of all, Little Mix are marking five whole years together as a girl group, after being put together on the 2011 series of the ITV talent show.
Jesy Nelson, Perrie Edwards, Leigh-Anne Pinnock and Jade Thirlwall each entered the competition as solo singers but were fused to create an incredible, hit-making, chart-topping, jaw-dropping four-piece unit.
They celebrated their anniversary with a throwback video on their Twitter page, and fans of the group have shared their feelings over the milestone moment.
Many were crying, many were thrilled, and some just could not believe it.
Looking back at the girls, who were mentored by Tulisa during the eighth season of The X Factor, they haven't changed all that much, apart from the odd mini-makeover.
Elsewhere in pop-land, One Direction fans are celebrating the fifth anniversary of their debut single What Makes You Beautiful.
1D were formed the year before Little Mix, on the 2010 series of The X Factor and, while they didn't win the show like the girls did, they have gone on to have more success than one can shake a stick at.
Harry Styles, Niall Horan, Liam Payne, Louis Tomlinson and Zayn Malik were created by Simon Cowell and Nicole Scherzinger who, at the time, was a guest judge.
Needless to say, the handsome young men have pretty much owned the pop music world in the years since they came third on the TV talent show, and their devoted Directioners caused #5YearsOfWMYB to become a trending topic on Twitter.
And that's even without Zayn being part of the group any more, as he left in March last year. The boys have also disbanded and are currently on hiatus.
Check out some of the best - and emotional - fan reactions to the anniversary. Basically, they want One Direction to come back.